Changes

==Types of filtration==

==Types of filtration==

Two common types of filter media used in stormwater treatment are granular media, such as [[sand]], and membranes:   

Two common types of filter media used in stormwater treatment are granular media and membranes:   

'''Granular media''' is a multilayer lattice or matrix that traps solids as water flows through the tortuous channels in the media.  

'''Granular media''' is a multilayer lattice or matrix that traps solids as water flows through the tortuous channels in the media. Examples of granular media include [[sand]] and [[Aggregates|gravel]].

'''Membranes''' have very thin separation lattices with openings or pores that remove all particles larger than the nominal pore size of the filter at the surface, thereby acting much like a sieve. Membranes are often pleated to increase the surface area, allowing for more particles to be trapped prior to clogging. Care should be taken when selecting the type of [[Geotextiles|geotextile]] used in an LID system.

'''Membranes''' have very thin separation lattices with openings or pores that remove all particles larger than the nominal pore size of the filter at the surface, thereby acting much like a sieve. Membranes are often pleated to increase the surface area, allowing for more particles to be trapped prior to clogging. Care should be taken when selecting the type of [[Geotextiles|geotextile]] used in an LID system.